The computer aided diagnosis (CAD) system may be used to detect lesions, display diagnosis results relating to the lesions to doctors, and support doctors to locate, diagnose and quantitatively analyze the lesions (e.g., a pulmonary nodule, a breast calcification, a breast mass, polyp, etc.) in medical images to reduce misdiagnoses and missed diagnoses and increase correct diagnosis rate. Accordingly, it would be desirable to improve the efficiency and accuracy of the detection and/or diagnosis of a CAD system.